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Updated: Jun 27, 2026
Experimental Metastasis Assay
Published on: August 24, 2010
Thrombospondin 2 inhibits metastasis of human malignant melanoma through microenvironment-modification in
Tsuyoshi Chijiwa1, Yoshiyuki Abe, Norihiro Ikoma
1Department of Pathology, Tokai University School of Medicine, Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
Abstract:
Thrombospondin (TSP) 2 interacts with matrix metalloproteinases (MMPs) and matrix serine proteases such as plasminogen activator (PA). Malignant melanoma is an aggressive human neoplasm showing aggressive metastatic features. We examined the effects of TSP2 gene introduction in the human malignant melanoma cell line A375. We established three clones transfected with human TSP2 (A375/TSP2). The in vitro invasiveness was remarkably suppressed (42-61%) in the TSP2-transfectants, while growth properties were preserved. The A375/TSP2 showed significantly decreased liver metastatic potential (liver weight: 3.88+/-0.30 g in A375/TSP2, 7.07+/-0.67 g in vector-transfectant (A375/V), p<0.01, Mann-Whitney U test) in super immuno-deficient mice (NOD/SCID/gammacnull, NOG). The PA inhibitor-1 (PAI-1) and PAI-2 mRNAs were significantly overexpressed in A375/TSP2. The increased activities of PAI-1 and PAI-2 were confirmed by reverse zymography. The vascularity of metastatic lesions was significantly decreased in A375/TSP2 (vascular density: 0.62+/-0.15% in A375/TSP2, 4.96+/-0.61% in A375/V, p<0.01, Welch test). These results suggest that TSP2 suppresses hematogenous metastasis through microenvironment-modification including PAI up-regulation and anti-vascularization in human malignant melanoma.
Insights
Thrombospondin 2 (TSP2) gene introduction suppressed malignant melanoma cell invasiveness and liver metastasis in mice. TSP2 gene therapy also reduced tumor vascularity by up-regulating plasminogen activator inhibitors.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Metastasis Research
Background:
- Malignant melanoma is an aggressive cancer with high metastatic potential.
- Thrombospondin 2 (TSP2) is known to interact with proteases involved in tumor progression.
- Understanding TSP2's role in melanoma metastasis is crucial for developing new therapies.
Purpose of the Study:
- To investigate the effect of TSP2 gene introduction on the metastatic potential of human malignant melanoma cells (A375).
- To analyze the impact of TSP2 on in vitro invasiveness, in vivo liver metastasis, and tumor microenvironment factors.
Main Methods:
- Established human malignant melanoma cell line A375 clones transfected with human TSP2 (A375/TSP2).
- Assessed in vitro invasiveness and growth properties of A375/TSP2 cells.
- Evaluated liver metastatic potential in super immunodeficient mice (NOG).
- Measured mRNA expression of plasminogen activator inhibitor-1 (PAI-1) and PAI-2, and assessed protease activity via reverse zymography.
- Quantified vascularity in metastatic lesions using immunohistochemistry.
Main Results:
- TSP2 gene introduction significantly suppressed in vitro invasiveness (42-61%) while preserving cell growth.
- A375/TSP2 cells exhibited significantly reduced liver metastatic potential in vivo.
- Overexpression of PAI-1 and PAI-2 mRNA and increased activity were observed in A375/TSP2 cells.
- Tumor vascularity in metastatic lesions was significantly decreased in the TSP2-transfectants.
Conclusions:
- TSP2 gene introduction effectively suppresses melanoma cell invasiveness and hematogenous metastasis.
- TSP2 modifies the tumor microenvironment by up-regulating PAIs and reducing vascularization.
- TSP2 holds potential as a therapeutic agent for combating melanoma metastasis.
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